This invention relates to molded case circuit breakers and more particularly to a circuit breaker which has a common crossbar member for operation of all poles of a multi-pole circuit breaker simultaneously.
A circuit breaker normally serves the dual function of opening and closing a circuit. Where the circuit breaker consists of two or more poles, it is desirable to open or close all poles of the breaker at the same time under normal tripping conditions or normal overcurrent conditions. To accomplish this, there have been arrangements wherein the operating handles for each pole have been mechanically tied together externally so that operation of one handle would operate all handles. More modern circuit breakers are single-handle devices, that is, for a multi-pole arrangement there is but one operating handle. In this arrangement, the tripping mechanisms are internally mechanically linked by a common shaft so that operation of the handle opens or closes all poles. It can be understood, that these arrangements require more parts and are thus most costly than more simple arrangements. However, it is desirable to gang operate the poles of a multi-pole circuit breaker.
U.S. Pat. No. 4,409,573 which issued on Oct. 11, 1983 to Bernard DiMarco and Andrew J. Kralik disclose a circuit breaker which has a contact arm which is pivotable about a cross bar. In the three-pole version, the other two poles of the circuit breaker are also connected to the crossbar to facilitate opening and closing of all three poles of the circuit breaker in unison under normal operating conditions. However, the tripping mechanisms are connected by a shaft extending through all three poles. Accordingly, it can be appreciated that it would be highly desirable to provide a simple mechanism for operating the contact arms of all poles of a multi-pole circuit breaker in unison under normal conditions which is simple and can be changed in the field.
Because many circuit breakers are used in control panels and other apparatus where space is limited and at a premium, there is a tendency to minimize the size of circuit breakers where possible. Thus, it can be appreciated that it would be highly desirable to provide a compact circuit breaker arrangement for a multi-pole circuit breaker in which the contacts of the poles operate in unison during normal conditions.
Accordingly, it is an object of this invention to provide a compact multi-pole circuit breaker arrangement.
Another object of this invention is to provide a circuit breaker arrangement which has the contact arms operating in unison during normal conditions.
Another object of this invention is to provide a compact circuit breaker arrangement which is simple to assemble.